The graphics pack for the latest version of the mod has been split into three distinct downloads. This was done to help people with slow or unreliable internet connections download the mod's interface and pictures, as the original graphics pack was getting too large. The new downloads are Major Models (unit pictures for the big countries), Minor Models (unit pictures for everyone else), and Misc (interface, tech, event, leader, etc. pictures).
The graphics packs are optional and the mod will run without them, but the mod will look much better with the additional graphics. Install instructions can be found in each download's description section.